This invention relates to a light emitting diode display panel composed of a plurality of light emitting diode elements.
As shown in FIG. 3, prior art display panels using light emitting diodes are typically composed of red (R) and green (G) light emitting diodes each including a stem of 3-5 mm .PHI. in outer diameter and disposed alternately in arrays such that mixed colors can be displayed. With a display panel thus structured, however, only a low brightness can be obtained because the number of light emitting diodes that can be disposed per unit area is limited by their external dimensions. In order to improve the brightness of a display panel, therefore, it may be considered to make use of two-color light emitting diode elements 2 structured as shown in FIG. 4 with two light emitting diode chips 2b and 2c on a single stem 2a emitting light of different colors such as red from one 2b and green from the other 2c. With two-color light emitting diode elements 2 like this, the number of light emitting diode chips per unit area of a display panel can be doubled and hence brighter panels can be made available.
Since the individual chips 2b and 2c of a two-color light emitting diode element 2 are disposed on the stem 2a away from the optical axis of the element 2 as shown in FIG. 4, however, red light and green light are emitted in mutually different directions as shown in FIG. 5 wherein numeral 3b indicates the directional intensity distribution of red light from the red light emitting diode chip 2b of FIG. 4 and numeral 3c indicates that of green light from the green light emitting diode elements like this are arranged as shown in FIG. 6 such that mutually adjacent chips emit different colors, different colors will be seen, depending upon the position of the viewers with respect to the panel. The view from the right-hand side or left-hand side, for example, will see different colors alternately along vertical lines.